Fabrication and thermoelectric properties of NaCo/sub 2/O/sub 4/ crystal

Large Na/sub x/CoO/sub 2/ (x /spl les/ 1) crystals that were thin along the c-axis were grown by a flux method. X-ray diffraction measurement showed that the crystals grown were NaCo/sub 2/O/sub 4/ (/spl gamma/ phase) and Na/sub x/CoO/sub 2/ (x=1, 0.75; /spl alpha/, /spl alpha/' phase). The largest NaCo/sub 2/O/sub 4/ crystal obtained was 5x5x0.I min. We measured the in-plane thermoelectric properties of the NaCo/sub 2/O/sub 4/ crystals. The thermoelectric power increased with temperature and reached 100 /spl mu/V/K at 450 K.